This invention relates to a ground guidance and control system for docking and undocking aircraft at the gate at an airport terminal.
The usual system in use in the United States and many foreign countries for guiding taxying aircraft to parking position employs a painted line on the taxiway which the pilot follows visually with the aid of manual signals from ground personnel to keep him on course and to tell him when to stop. At departure time he must call ground control by radio telephone for verbal clearance to start engines and push back from the gate.
Various more sophisticated systems have been proposed, for example those shown in U.S. Pat. Nos. 3,674,226, 3,729,262, 3,775,741 and 3,821,697. Still others are described in, for example, American Airlines Flight Manual - Part I, Sec. 4, page 73 (Oct. 17, 1973); id. Part II, 19:5 (May 5, 1972); id. Part I, Sec. 4, page 69 (Apr. 23, 1973); and id. Part I, Sec. 4, page 70 (Jan. 18, 1974).
All systems so far proposed, so far as I am aware, suffer from one or more drawbacks. For example they may employ expensive and often undependable and nondurable underground pressure sensors which give signals of the aircraft's position; or they may be incapable of ready adaptation to different aircraft; or they may require the pilot to respond visually to signals simultaneously transmitted from different directions or from different distances; or they may require that the pilot's eyes be positioned on a precise line passing through the center of the windshield, thus making the system unreliable in any other position. None of them now in use, so far as I am aware, makes it possible to dispense with any ground personnel and none of them is compatible with the air traffic control computers whereby, by appropriate programming of the computers, the pilot may be signaled automatically when to start engines and when to push back and/or taxi from the gate for departure.